OFFSET
1,1
LINKS
Harvey P. Dale, Table of n, a(n) for n = 1..1000
FORMULA
a(n) = A091567(n) - 1.
MATHEMATICA
Select[Prime[Range[200]]-1, PrimeQ[#^2+#-1]&] (* Harvey P. Dale, Jan 20 2019 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Lekraj Beedassy, Dec 23 2007
STATUS
approved